Effect of Eucalyptus and Mentha leaves and Curcuma rhizomes on Tyrophagus putrescentiae (Schrank) (Acarina: Acaridae) in wheat

Varying concentrations of powdered leaves of Eucalyptus and Mentha and rhizomes of Curcuma were evaluated in controlling Tyrophagus putrescentiae in wheat flour. At higher concentrations, all these plant materials significantly decreased the population build-up of the mite. Eucalyptus and Mentha leaf powders were effective at concentrations ranging from 100 to 5% in bringing about a decrease in the fecundity of the mite and reducing the egg numbers to 51.66 and 25.49 per female, respectively, as compared to 98.16 eggs per female in the controls. Rhizomes of Curcuma were effective even at a concentration of 0.1% reducing the egg laying to 7.66 eggs per female in wheat flour. These materials were more deleterious to immature stages (ova and larvae) than to the mature stages of T. putrescentiae. When tested on whole grains of wheat these plant materials showed more pronounced effects in controlling the mite population compared to that in wheat flour. Curcuma rhizomes were the most promising for possible use against T. putrescentiae.